Alert control apparatus and alert control method

ABSTRACT

An alert control apparatus that notifies a driver in advance of a transfer of control relating to a driving operation from an automatic driving function to the driver by controlling an alert device mounted on a vehicle, which is equipped with the automatic driving function, includes: an estimator that estimates an occurrence of a change execution situation that requires a lane change under a condition in which the driving operation of the vehicle is controlled by the automatic driving function; a determiner that determines a level of difficulty of lane change control based on a plurality of travel environment factors in the change execution situation; and a notification device that notifies the driver of a possibility of the transfer of the control together with a reason of the transfer of the control with a notification mode corresponding to the level using the alert device.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2016-12760filed on Jan. 26, 2016, the disclosure of which is incorporated hereinby reference.

TECHNICAL FIELD

The present disclosure relates to an alert control apparatus that, in avehicle equipped with an automatic driving function, notifies a driverin advance of a transfer of control relating to a driving operation fromthe automatic driving function to the driver and an alert controlmethod.

BACKGROUND ART

Conventionally, even in a system capable of performing a drivingoperation on behalf of a driver such as an automatic driving supportapparatus disclosed in Patent Literature 1, a condition in which it isdifficult to continue automatic driving is unavoidably caused by areduction in the reliability of information that identifies an ownvehicle position. Thus, in the automatic driving support apparatus inPatent Literature 1, the degree of continuability of automatic drivingis indexed to determine high or low of a possibility that continuationof automatic driving immediately becomes impossible. The driver isnotified in advance of the high or low of the possibility of a transferof control with an alert mode corresponding to the determination result.Accordingly, the driver can receive the control from the automaticdriving support apparatus after recognizing the high or low of thepossibility that continuation of automatic driving immediately becomesimpossible.

However, in the automatic driving support apparatus in Patent Literature1, the notification of the possibility that automatic driving cannot becontinued is performed on the basis of a reduction in the reliability ofeach sensor that identifies the own vehicle position. Thus, it isdifficult to ensure sufficient time from the performance of thenotification to the start of the control transfer. In addition, sinceonly the high or low of the possibility of the transfer is notified, thedriver receives the control with no understanding of the state of asituation in which the control is transferred. As a result, the driveris likely to feel troublesomeness such that the driver is forced tochange driving under the initiative of a system of the automatic drivingsupport apparatus.

PRIOR ART LITERATURES Patent Literature

Patent Literature 1: JP-2015-179037-A

SUMMARY OF INVENTION

It is an object of the present disclosure to provide an alert controlapparatus and an alert control method that notifies a driver in advanceof a transfer of control so as not to give the driver a troublesomefeeling such that the driver is forced to change driving under theinitiative of a system.

According to a first aspect of the present disclosure, an alert controlapparatus that notifies a driver in advance of a transfer of controlrelating to a driving operation from an automatic driving function tothe driver by controlling at least one alert device mounted on avehicle, which is equipped with the automatic driving function forperforming the driving operation on behalf of the driver, the alertcontrol apparatus includes: an estimator that estimates an occurrence ofa change execution situation that requires a lane change under acondition in which the driving operation of the vehicle is controlled bythe automatic driving function; a determiner that determines a level ofdifficulty of lane change control based on a plurality of travelenvironment factors in the change execution situation estimated by theestimator; and a notification device that notifies the driver of apossibility of the transfer of the control together with a reason of thetransfer of the control with a notification mode corresponding to thelevel determined by the determiner using the at least one alert device.

In the alert control apparatus described above, when the occurrence of achange execution situation that requires a lane change is estimated, thedriver is notified in advance of both of the possibility of a transferof control relating to a driving operation and the reason of the controltransfer. Such an advance notification based on the situation estimationmakes it possible to ensure sufficient time from the performance of thenotification to the start of the transfer.

In addition, the reason of the control transfer is notified with anotification mode corresponding to the level of difficulty of lanechange control. Accordingly, the driver can initiatively receive thecontrol relating to the driving operation after previously understandingthe state of the change execution situation that requires a lane changeand making advance preparations. Thus, it is possible to reduce atroublesome feeling of the driver such that the driver is forced tochange driving under the initiative of a system relating to theautomatic driving function.

According to a second aspect of the present disclosure, an alert controlmethod for notifying a driver in advance of a transfer of controlrelating to a driving operation from an automatic driving function tothe driver by controlling at least one alert device mounted on avehicle, which is equipped with the automatic driving function forperforming the driving operation on behalf of the driver, the alertcontrol method executed by at least one processor, includes: estimatingan occurrence of a change execution situation that requires a lanechange under a condition in which the driving operation of the vehicleis controlled by the automatic driving function; determining a level ofdifficulty of lane change control based on a plurality of travelenvironment factors in an estimated change execution situation; andnotifying the driver of a possibility of the transfer of the controltogether with a reason of the transfer of the control with anotification mode corresponding to a determined level using the at leastone alert device.

In the alert control method described above, when the occurrence of achange execution situation that requires a lane change is estimated, thedriver is notified in advance of both of the possibility of a transferof control relating to a driving operation and the reason of the controltransfer. Such an advance notification based on the situation estimationmakes it possible to ensure sufficient time from the performance of thenotification to the start of the transfer.

In addition, the reason of the control transfer is notified with anotification mode corresponding to the level of difficulty of lanechange control. Accordingly, the driver can initiatively receive thecontrol relating to the driving operation after previously understandingthe state of the change execution situation that requires a lane changeand making advance preparations. Thus, it is possible to reduce atroublesome feeling of the driver such that the driver is forced tochange driving under the initiative of a system relating to theautomatic driving function.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a block diagram illustrating the entire configuration of anHCU, an automatic driving ECU, a vehicle control ECU, and the like in afirst embodiment;

FIG. 2 is a diagram illustrating an example of a specific configurationof the HCU, the automatic driving ECU, and the vehicle control ECU;

FIG. 3 is a flowchart illustrating details of an advance notificationprocess performed by the HUC;

FIG. 4 is a diagram illustrating a concrete example of a scene in whicha preliminary authority transfer is performed;

FIG. 5 is a block diagram illustrating the entire configuration of anHCU, an automatic driving ECU, a vehicle control ECU, and the like in asecond embodiment; and

FIG. 6 is a block diagram illustrating the entire configuration of anHCU, a transfer control ECU, an automatic driving ECU, a vehicle controlECU, and the like in a third embodiment.

EMBODIMENTS FOR CARRYING OUT INVENTION

Hereinbelow, a plurality of embodiments of the present disclosure willbe described with reference to the drawings. Corresponding elementsbetween the respective embodiments may be denoted by the same referencesigns to avoid repetitive description. In each of the embodiments, whenonly a part of a configuration is described, a configuration of theother preceding embodiments can be applied to the other part of theconfiguration. Further, in addition to a combination of configurationsclearly stated in each of the embodiments, configurations of a pluralityof embodiments may be partially combined even if not clearly statedunless there is an obstacle in the combination.

First Embodiment

A human machine interface (HMI) control unit (HCU) 20 according to afirst embodiment of the present disclosure illustrated in FIGS. 1 and 2is mounted on a vehicle A equipped with an automatic driving function.An automatic driving ECU 60 and a vehicle control ECU 80 are mounted, asan electronic control unit for implementing the automatic drivingfunction, on the vehicle A. The HCU 20 is electrically connected to aplurality of alert devices 10 which notifies a driver of information anda plurality of detectors 15 which detects a state of the driver inaddition to the automatic driving ECU 60.

The automatic driving ECU 60 exhibits the automatic driving functioncapable of performing a driving operation on behalf of the driver of thevehicle A by performing acceleration and deceleration control andsteering control for the vehicle A in cooperation with the vehiclecontrol ECU 80. The automatic driving ECU 60 is mainly composed of amicrocomputer which includes a processor 61 a, a RAM 63 a, a storagemedium 64 a, and an input/output interface 65 a. The automatic drivingECU 60 is electrically connected to a GNSS receiver 71, a lidar 72, amillimeter wave radar 73, a camera unit 74, a map database 75, a V2Xreceiver 76, and the like. The automatic driving ECU 60 acquiresinformation required for automatic driving from these elements (71 to76).

The global navigation satellite system (GNSS) receiver 71 receivespositioning signals from a plurality of artificial satellites. The GNSSreceiver 71 measures the current position of the vehicle A on the basisof the received positioning signals. The GNSS receiver 71 successivelyoutputs the measured positional information of the vehicle A to theautomatic driving ECU 60.

The lidar 72, the millimeter wave radar 73, and the camera unit 74 areautonomous sensors each of which detects moving objects such as apedestrian and another vehicle and also stationary objects such as afallen object on a road, a traffic light, a guard rail, a curb, a roadsign, a road marking, and a lane marking. Each of the lidar 72, themillimeter wave radar 73, and the camera unit 74 successively outputsdetected object information relating to detected moving and stationaryobjects to the automatic driving ECU 60.

The lidar 72 emits a laser beam in a traveling direction of the vehicleA and receives the laser beam reflected by a moving object or astationary object present in the traveling direction to acquire detectedobject information. The millimeter wave radar 73 emits a millimeter wavein the traveling direction of the vehicle A and receives the millimeterwave reflected by a moving object or a stationary object present in thetraveling direction to acquire detected object information. Themillimeter wave radar 73 is capable of detecting a more distant objectthan the lidar 72 is.

The camera unit 74 includes a monocular or compound-eye front camerawhich captures an image of a front region in front of the vehicle A andan image processor which analyzes the front region image captured by thefront camera. The camera unit 74 extracts a moving object or astationary object included in the front region image to acquire detectedobject information.

The map database 75 is a storage medium that stores many map data itemstherein. The map data includes structure information such as thecurvature, the gradient, and the length of a section of each road, andnontemporary traffic regulation information such as a speed limit andone-way traffic. The map database 75 causes the automatic driving ECU 60to acquire map data around the current position of the vehicle A and inthe traveling direction of the vehicle A.

The V2X receiver 76 exchanges information with an onboard communicationdevice which is mounted on another vehicle and a roadside device whichis installed on the road side by wireless communication. The V2Xreceiver 76 receives temporary traffic regulation information,congestion information, and weather information by vehicle-to-vehiclecommunication with the onboard communication device and road-to-vehiclecommunication with the roadside device and successively outputs thereceived information items to the automatic driving ECU 60. Thetemporary traffic regulation information includes, for example,information of lane regulation and closed road which occur on a road inthe traveling direction of the vehicle A due to an accident or aconstruction work. The congestion information includes, for example,information of the degree of traffic congestion and the condition oftraffic flow (e.g., a traveling speed) on a road in the travelingdirection. The weather information includes, for example, information ofthe amount of rainfall, the amount of snowfall, and the occurrence offog on a road in the traveling direction.

The automatic driving ECU 60 constructs a self-diagnostic functionsection 64, a travel environment recognition section 61, a travel plangenerator 62, and a driving change determiner 63 as functional blocksrelating to automatic driving by executing an automatic driving programstored in the storage medium 64 a by the processor 61 a. Theself-diagnostic function section 64 diagnoses whether each function ofthe automatic driving ECU 60 is in normal operation.

The travel environment recognition section 61 recognizes a travelenvironment of the vehicle A by combining positional informationacquired from the GNSS receiver 71, detected object information acquiredfrom each of the autonomous sensors, and map data acquired from the mapdatabase 75 with each other. Specifically, the travel environmentrecognition section 61 recognizes the shape and a moving state of anobject around the vehicle A within a detection range of each of theautonomous sensors mainly on the basis of the detected objectinformation and generates a virtual space that reproduces an actualtravel environment. In addition, the travel environment recognitionsection 61 recognizes a travel environment outside the detection rangeof each of the autonomous sensors using each information acquired fromthe map data and the V2X receiver 76.

The travel plan generator 62 generates a travel plan for causing thevehicle A to automatically travel by the automatic driving function onthe basis of the travel environment recognized by the travel environmentrecognition section 61. The travel plan includes a long and medium-termtravel plan and a short-term travel plan. The travel plans formulated bythe travel plan generator 62 are successively output from the automaticdriving ECU 60 to the HCU 20 and the vehicle control ECU 80 togetherwith operating information which indicates whether automatic driving isactive.

The long and medium-term travel plan defines a route to a destinationfor the vehicle A. The route defined by the long and medium-term travelplan extends to a position outside the detection range of each of theautonomous sensors. The long and medium-term travel plan reflectsstructure information and nontemporary traffic regulation informationincluded in the map data and temporary traffic regulation informationreceived from the outside. As a result, in the route defined by the longand medium-term travel plan, not only a direction that should befollowed by the vehicle A at a branch point, but also a lane that issuitable for smooth passage at a lane regulation area and a branch pointis selected.

The short-term travel plan defines a scheduled travel track forachieving travel following the long and medium-term travel plan usingthe virtual space around the vehicle A generated by the travelenvironment recognition section 61. In the short-term travel plane,specifically, the execution of steering for a lane change, accelerationand deceleration for speed control, and quick braking for avoidingcollision is determined.

The driving change determiner 63 determines whether it is possible tocontinue a driving operation by the automatic driving function. Thedriving change determiner 63 determines that it is difficult orimpossible to continue the driving operation by the automatic drivingfunction when it is difficult to generate a short-term travel plan basedon the recognized travel environment. In addition, the driving changedeterminer 63 determines that it is difficult or impossible to continuethe driving operation by the automatic driving function when a failurein a system has been detected on the basis of each of diagnosis resultsby the self-diagnostic function section 64 of the automatic driving ECU60 and a self-diagnostic function section 82 of the vehicle control ECU80 (described below). The driving change determiner 63 starts a drivingchange from the automatic driving function to the driver by outputting atransfer execution signal for executing a transfer of control relatingto a driving operation to the HCU 20 and the vehicle control ECU 80.

The vehicle control ECU 80 is electrically connected to an onboardactuator group 90 which is mounted on the vehicle A and integrallycontrols acceleration and deceleration and steering of the vehicle A.The vehicle control ECU 80 is mainly composed of a microcomputer whichincludes a processor 81 a, a RAM 83 a, a storage medium 84 a, and aninput/output interface 85 a. The onboard actuator group 90 includes, forexample, a throttle actuator, an injector, a brake actuator, a motorgenerator for driving, and a steering actuator.

The vehicle control ECU 80 constructs an actuator controller 81 and theself-diagnostic function section 82 as functional blocks relating tovehicle control by executing a vehicle control program stored in thestorage medium 84 a by the processor 81 a. The actuator controller 81generates a control signal having contents following the scheduledtravel track formulated by the travel plan generator 62 in a state inwhich the automatic driving function is active and outputs the generatedcontrol signal to the onboard actuator group 90. In addition, theactuator controller 81 generates a control signal having contentsfollowing a driving operation input by the driver in a state in whichthe automatic driving function is inactive, for example, when a transferexecution signal has been acquired and outputs the generated controlsignal to the onboard actuator group 90. The self-diagnostic functionsection 82 diagnoses whether each function of the vehicle control ECU 80is in normally operation.

Each of the alert devices 10 notifies occupants of the vehicle Aincluding the driver of various pieces of information relating to thevehicle A on the basis of alert control information output by the HCU20. The alert device 10 may be previously mounted on the vehicle A, orcarried into a vehicle cabin by an occupant of the vehicle A so as to betemporarily mounted on the vehicle A. The alert devices 10 include aspeaker 12, a head-up display (HUD) device 13, and a touch sensepresentation device 14.

The speaker 12 gives the driver or the like an alert through the senseof hearing by reproducing an alert sound or a message voice inside thevehicle cabin. The HUD device 13 gives the driver an alert through thesense of sight by forming a virtual image in front of the driver. Thetouch sense presentation device 14 is, for example, a vibration devicewhich is disposed on a steering wheel or a footrest which is capable ofchanging a posture. The touch sense presentation device 14 gives thedriver an alert through the sense of touch.

Each of the detectors 15 detects driver information relating to adriving state of the driver and successively outputs the detected driverinformation to the HCU 20. The detectors 15 include a steering sensor16, a brake sensor 17, and a driver status monitor (DSM) 18.

The steering sensor 16 is a sensor that detects a grasp on the steeringwheel or a sensor that detects an input of a steering torque to thesteering wheel. The steering sensor 16 detects, as driver information,whether a steering operation by the driver is possible. The brake sensor17 is, for example, a sensor that detects a placement of the foot of thedriver on a brake pedal. The brake sensor detects, as driverinformation, whether a brake operation by the driver is possible.

The DSM 18 includes a near-infrared light source, a near-infraredcamera, and a control unit which controls the near-infrared light sourceand the near-infrared camera. The DSM 18 captures an image of the faceof the driver with near-infrared light applied by the near-infraredlight source using the near-infrared camera. The DSM 18 extracts, forexample, the direction of the face of the driver and an opening state ofthe eyes of the driver from the captured image to detect, as driverinformation, looking-aside and a reduction in an awakening level in thedriver.

The HCU 20 is an electronic control unit that integrally controlsacquisition of operating information input by the driver and informationpresentation to the driver. The HCU 20 is an electronic control unitmainly composed of a microcomputer which includes a main processor 21, adrawing processor 22, a RAM 23, a storage medium 24, and an input/outputinterface 25. The HCU 20 constructs a preliminary authority transferprocessor 30, a main authority transfer processor 40, and an HMIcontroller 50 as functional blocks by executing an alert control programstored in the storage medium 24 by each of the processors 21, 22.

The preliminary authority transfer processor 30 is a functional blockthat performs a process of notifying the driver in advance of a transferof the control from the automatic driving function to the driver beforethe start of the transfer (hereinbelow, referred to as a “preliminaryauthority transfer”). The preliminary authority transfer is performedbefore determination of a driving change by the driving changedeterminer 63 so as to be started prior to a start timing of an actualtransfer by a previously set grace period (e.g., approximately 30seconds). Thus, in the preliminary authority transfer, the driver isnotified of not determination of the transfer of the control, but apossibility of the transfer of the control. In addition, the driver isalso notified of a reason why it has been determined that there is apossibility of the transfer of the control. In the preliminary authoritytransfer processor 30, a zone estimator 31 and a determiner group 32including at least a plurality of (three) determiners 33 to 35 areconstructed as sub-functional blocks relating to the preliminaryauthority transfer.

The zone estimator 31 determines whether the driving operation of thevehicle A is being controlled by the automatic driving function on thebasis of operating information output from the automatic driving ECU 60.The zone estimator 31 estimates the occurrence of a change executionsituation that requires a lane change (hereinbelow, referred to as an“LC scheduled zone”) on the basis of the long and medium-term travelplan formulated by the travel plan generator 62 under a condition inwhich the automatic driving function is active.

Specifically, when a merging point is present in the traveling directionof the vehicle A, that is, on a route formulated by the travel plangenerator 62, the zone estimator 31 estimates the occurrence of the LCscheduled zone. The merging point is set at a point that merges into amain through lane relating to an interchange (IC), a junction (JCT), anda service area (SA) and a parking area (PA) on the route on the basis ofthe map data. In addition, the zone estimator 31 estimates theoccurrence of the LC scheduled zone also when there is a lane regulationon the route on the basis of temporary traffic regulation informationacquired by the V2X receiver 76.

The determiner group 32 estimates the level of difficulty of lane changecontrol (hereinbelow, referred to as an “LC level”) on the basis of aplurality of travel environment factors in the LC scheduled zoneestimated by the zone estimator 31. Each of the determiners 33 to 35determines whether to raise the LC level on the basis of the travelenvironment factors which differ from each other. Accordingly, thedeterminer group 32 is capable of classifying the possibility of adriving change into a plurality of stages, specifically, four stages ofLC levels 0 to 3. As the LC level becomes higher, the degree ofdifficulty of lane change control becomes higher.

The first determiner 33 is capable of acquiring structure information ofa road in the LC scheduled zone as one of the travel environmentfactors. The first determiner 33 may acquire structure informationoutput from the map database 75 to the automatic driving ECU 60 from theautomatic driving ECU 60 or may extract structure information reflectedin the long and medium-term travel plan. The first determiner 33determines an LC level resulting from the road structure as a firstdriving change possibility using the acquired structure information. Forexample, when an acceleration lane for merging into the main throughlane has a rising gradient and the acceleration lane is shorter than apredetermined distance, the first determiner 33 affirms the firstdriving change possibility and raises the LC level by one. On the otherhand, when the acceleration lane is horizontal and has a standarddistance, the first determiner 33 denies the first driving changepossibility and maintains the LC level.

The second determiner 34 acquires congestion information of a road inthe LC scheduled zone as one of the travel environment factors. Thesecond determiner 34 is capable of acquiring congestion informationoutput from the V2X receiver 76 to the automatic driving ECU 60 from theautomatic driving ECU 60. The second determiner 34 determines an LClevel resulting from the degree of traffic congestion as a seconddriving change possibility using the acquired congestion information.For example, when traffic flow (traveling speed) in an acceleration laneor a main through lane which merges with the acceleration lane is bad,the second determiner 34 affirms the second driving change possibilityand raises the LC level by one. On the other hand, when traffic flow inthe LC scheduled zone is smooth, the second determiner 34 denies thesecond driving change possibility and maintains the LC level.

The third determiner 35 acquires weather information in the LC schedulezone as one of the travel environment factors. The third determiner 35is capable of acquiring weather information output from the V2X receiver76 to the automatic driving ECU 60 from the automatic driving ECU 60.The third determiner 35 determines an LC level resulting from a weatherfactor as a third driving change possibility using the acquired weatherinformation. For example, when there is rainfall or snowfall or there isfog in an area including the LC scheduled zone, the third determiner 35affirms the third driving change possibility and raises the LC level byone. On the other hand, when a weather condition is good in the LCscheduled zone, the third determiner 35 denies the third driving changepossibility and maintains the LC level.

The main authority transfer processor 40 is a functional block thatperforms a process of notifying the driver of execution of a transfer ofcontrol (hereinbelow, referred to as a “main authority transfer”) whenthe control is transferred from the automatic driving function to thedriver. When the main authority transfer processor 40 acquires atransfer execution signal based on the determination by the drivingchange determiner 63 from the automatic driving ECU 60, the mainauthority transfer processor 40 causes the HMI controller 50 to generatealert control information for performing the main authority transfer.

The HMI controller 50 is a functional block that performs a processrelating to acquisition of driver information detected by the detector15 and a process relating to information presentation to the driverusing the alert device 10. In the HMI controller 50, a response detector51, a preliminary notification device 52, and a transfer notificationdevice 53 are constructed as sub-functional blocks relating to thepreliminary authority transfer and the main authority transfer.

The response detector 51 detects a response from the driver to thepreliminary authority transfer from driver information detected by eachof the detectors 15. The response detector 51 determines whether thedriver has grasped the steering wheel, the driver is in a state capableof operating the brake pedal, and the driver directs his/her sight tothe front by the preliminary authority transfer.

The preliminary notification device 52 performs a preliminary authoritytransfer which notifies the driver in advance of the possibility of atransfer of the control together with a reason of the transfer using atleast one of the plurality of alert devices 10. The preliminarynotification device 52 can perform the preliminary authority transferwith a notification mode corresponding to the level of difficulty oflane change control. Specifically, the preliminary notification device52 acquires a determination result by the determiner group 32 from thepreliminary authority transfer processor 30 and selects a preliminarynotification scenario corresponding to the acquired determinationresult. In the preliminary notification scenario, all travel environmentfactors that raise the LC level are included in a message to the driveras a reason of the transfer of the control among the travel environmentfactors used in the determination of the LC level, such as the structureinformation, the congestion information, and the weather information.

In addition, the preliminary notification device 52 selects apreliminary notification scenario that uses more alert devices 10 in thepreliminary authority transfer as the LC level becomes higher. Forexample, when the LC level is “1”, the preliminary authority transfer isperformed by virtual display by the HUD device 13. When the LC level is“2”, the preliminary authority transfer is performed by utterance by thespeaker 12 and virtual display by the HUD device 13. When the LC levelis “3”, the preliminary authority transfer is performed using all ofutterance by the speaker 12, virtual display by the HUD device 13, andtouch sense presentation by the touch sense presentation device 14. Thepreliminary notification device 52 generates alert control informationbased on the selected preliminary notification scenario and outputs thegenerated alert control information to the alert device 10.

The transfer notification device 53 selects a transfer notificationscenario for a main authority transfer on the basis of a command fromthe main authority transfer processor 40. The transfer notificationdevice 53 selects an optimal transfer notification scenario so that adriving change from the automatic driving function to the driver issmoothly performed by the main authority transfer. The transfernotification device 53 generates alert control information based on theselected transfer notification scenario and outputs the generated alertcontrol information to the alert device 10.

Details of the advance notification process for achieving thepreliminary authority transfer described above will be described withreference to FIG. 3 and also to FIG. 1. The advance notification processillustrated in FIG. 3 is started by the HCU 20 when an ignition of thevehicle A is turned on. The advance notification process is repeatedlystarted by the HCU 20 until the ignition of the vehicle A is turned off.

In S101, an operating state of the automatic driving function isdetermined. When it is determined in S101 that the driving operation ofthe vehicle A is being controlled by the automatic driving function, theprocess proceeds to S102. On the other hand, when a driving state is amanual driving state in which the driver performs the driving operationand it is determined in S101 that the automatic driving function isinactive, the advance notification process is temporarily finished.

The occurrence of an LC scheduled zone is estimated on the basis of along and medium-term travel plan in S102, and the process proceeds toS103. In S103, it is determined whether the occurrence of the LCscheduled zone has been estimated in S102. When the occurrence of the LCscheduled zone has not been estimated in S102, the process returns toS101. On the other hand, when the occurrence of the LC scheduled zonehas been estimated in S102, the process proceeds to S104.

Structure information of a road in the LC scheduled zone estimated inS102 is acquired in S104, and the process proceeds to S105. The firstdriving change possibility is determined in S105 on the basis of thestructure information acquired in S104, and the process proceeds toS106. When the structure information acquired in S104 indicates a risinggradient or a short distance of an acceleration lane in the LC scheduledzone, the first driving change possibility is affirmed, and the LC levelis raised by one in S105.

Congestion information of the road in the LC scheduled zone estimated inS102 is acquired in S106, and the process proceeds to S107. The seconddriving change possibility is determined in S107 on the basis of thecongestion information acquired in S106, and the process proceeds toS108. When the congestion information acquired in S106 indicates a badtraffic flow condition in the LC scheduled zone, the second drivingchange possibility is affirmed, and the LC level is raised by one inS107.

Weather information in the LC scheduled zone estimated in S102 isacquired in S108, and the process proceeds to S109. The third drivingchange possibility is determined in S109 on the basis of the weatherinformation acquired in S108, and the process proceeds to S110. When theweather information acquired in S108 indicates a bad weather conditionin the LC scheduled zone, the third driving change possibility isaffirmed, and the LC level is raised by one in S109.

In S110, it is determined whether the preliminary authority transfer isnecessary on the basis of each of determination results in S105, S107,and S109. When all of the first to third driving change possibilitiesare denied, and the LC level is zero, the preliminary authority transferis determined to be unnecessary in S110, and the process returns toS101. In this case, for example, a message that includes no transferreason such as “PLEASE PAY ATTENTION TO YOUR SURROUNDINGS” may bedisplayed or uttered by the control of the alert device 10.

On the other hand, when at least one of the first to third drivingchange possibilities is affirmed, the preliminary authority transfer isdetermined to be necessary in S110, and the process proceeds to S111. InS111, a preliminary notification scenario for the preliminary authoritytransfer is selected on the basis of the LC level according to thedetermination results in S105, S107, and S109, and the process proceedsto S112.

In S112 performed for the first time based on the affirmativedetermination in S110, a preliminary authority transfer based on thepreliminary notification scenario selected in S111 is executed, and theprocess proceeds to S113. In S113, it is determined whether a responsefrom the driver to the preliminary authority transfer executed in S112has been detected. When it is determined in S113 that the response fromthe driver has been detected, the process returns to S101. On the otherhand, when it is determined in S113 that no response from the driver hasbeen detected, S111 and S112 are executed again. When the LC level inthe determination by each of the determiners 33 to 35 is low (e.g., alevel 1), the process of determining the presence or absence of aresponse from the driver may be omitted by skipping S113.

In S111 and S112 performed for the second and subsequent times based onthe negative determination in S113, update information such as a liftingof the lane regulation, a deterioration or recovery of the weathercondition, and a recovery of the traffic flow is presented to thedriver. In addition, in S112 performed for the second and subsequenttimes, for example, a message such as “PLEASE PREPARE FOR DRIVINGCHANGE” is displayed or uttered as a response request to the driver.When the driver takes no appropriate driving state in response to themessage, the alert by the preliminary authority transfer is repeated.

An example of an actual scene in which the preliminary authoritytransfer is performed by an alert control method based on the aboveadvance notification process will be described with reference to FIG. 4and also to FIG. 1 on a time-series basis. FIG. 4 illustrates a case inwhich the automatic driving function is operated from an automaticdriving start point which is set between an entrance of an expresswayand a main through lane to an automatic driving end point which is setbetween the main through lane and an exit of the expressway. Theillustrated automatic driving is so-called gate-to-gate or lamp-to-lampautomatic driving.

When a long and medium-term travel plan is generated by actuation of theautomatic driving function with passage through the automatic drivingstart point, the zone estimator 31 instantly estimates the occurrence ofan LC scheduled zone on the basis of the presence of a merging point inan IC. The determiner group 32 determines that the LC level is “2” onthe basis of structure information which indicates a rising gradient ofan acceleration lane as the LC scheduled zone and congestion informationwhich indicates congestion in the LC scheduled zone. The preliminarynotification device 52 performs a preliminary authority transfer thatincludes both of the structure information and the congestioninformation that raise the LC level on the basis of the determinationresult of the determiner group 32. Specifically, in the preliminaryauthority transfer, a message such as “THERE ARE LOW VISIBILITY ANDCONGESTION. PLEASE GRASP STEERING WHEEL” is virtually displayed by theHUD device 13 and also uttered by the speaker 12.

When there is a lane regulation in the main through lane in theexpressway, the zone estimator 31 estimates the occurrence of an LCscheduled zone on the basis of the lane regulation. When all of thestructure information, the traffic information, and the weatherinformation have no travel environment factor that raises the LC level,the determiner group 32 determines that the LC level is “0”. As aresult, for example, a message such as “PLEASE PAY ATTENTION TO YOURSURROUNDINGS” is virtually displayed by the HUD device 13 as a normalalert.

When there are continuous branching and merging by the JCT, the zoneestimator 31 estimates the occurrence of an LC scheduled zone on thebasis of the presence of these points. The determiner group 32 sets asection in which a lane change is performed from a left lane (e.g., adriving lane) to a right lane (e.g., a passing lane) for branchingpreparation as a first LC scheduled zone, and acquires structureinformation, traffic information, and weather information relating tothe first LC scheduled zone. The determiner group 32 determines that theLC level is “2” on the basis of congestion information which indicatescongestion in the LC scheduled zone and weather information whichindicates rainfall in the LC scheduled zone. The preliminarynotification device 52 performs a preliminary authority transfer thatincludes both of the congestion information and the weather informationthat raise the LC level on the basis of the determination result of thedeterminer group 32. Specifically, in the preliminary authoritytransfer, a message such as “THERE ARE RAINFALL AND CONGESTION. PLEASEPAY PARTICULAR ATTENTION TO YOUR SURROUNDINGS” is virtually displayed bythe HUD device 13 and also uttered by the speaker 12.

Then, the determiner group 32 sets a merging point from the JCT into themain through lane as a second LC scheduled zone, and acquires additionalstructure information, traffic information, and weather informationrelating to the second LC scheduled zone. The determiner group 32determines that an additional information presentation by thepreliminary authority transfer is unnecessary on the basis of structureinformation which indicates that an acceleration lane as the second LCscheduled zone has a standard length longer than a predetermineddistance and congestion information which indicates that traffic flow issmooth.

When the vehicle A merges into the main through lane after dropping inat a SA or a PA, the zone estimator 31 estimates the occurrence of an LCscheduled zone on the basis of the presence of a merging point from theSA or the PA. The determiner group 32 determines that the LC level is“1” on the basis of structure information which indicates that anacceleration lane is shorter than the predetermined distance. Thepreliminary notification device 52 performs a preliminary authoritytransfer that includes the structure information that raises the LClevel on the basis of the determination result of the determiner group32. Specifically, in the preliminary authority transfer, a message suchas “THIS IS MERGING WITH SHORT ACCELERATION LANE. PLEASE PAY ATTENTIONTO YOUR SURROUNDINGS” is virtually displayed by the HUD device 13.

In the first embodiment described above, when the occurrence of an LCscheduled zone is estimated, the driver is notified in advance of bothof the possibility of a transfer of control and the reason of thecontrol transfer by performing a preliminary authority transfer. Such anadvance notification based on the situation estimation makes it possibleto ensure sufficient time from the performance of the notification tothe start of the transfer.

In addition, the reason of the control transfer is notified with anotification mode corresponding to the level of difficulty of lanechange control. Accordingly, the driver can initiatively receive thecontrol relating to the driving operation after previously understandingthe state of the LC scheduled zone and making advance preparations.Thus, the HCU 20 can reduce a troublesome feeling of the driver suchthat the driver is forced to change driving under the initiative of asystem relating to the automatic driving function.

Further, the driver who has been given sufficient time before the startof a driving change and thus understood the state of the LC scheduledzone in which the driving change is performed can also acquire thecontrol from the automatic driving function on his/her own will aftercompleting advance preparations for the driving change. As describedabove, override can be easily performed by performing the preliminaryauthority transfer. According to such override, the driver is furtherless likely to feel the troublesomeness such that the driver is forcedto change driving.

Further, in the first embodiment, structure information of a road suchas an acceleration lane to be an LC scheduled zone is used in thedetermination of the level of difficulty of lane change control. Whenthe acceleration lane to be the LC scheduled zone has a rising gradientand the acceleration lane is short, the lane change control is likely tobe difficult. Thus, the HCU 20 can accurately perform the leveldetermination in advance by using the structure information as a travelenvironment factor. In addition, when the structure information such aslow visibility caused by the rising ingredient and the short length ofthe acceleration lane is presented by the preliminary authoritytransfer, the driver can receive the control from the automatic drivingfunction after understanding the state of the acceleration lane indetail.

Further, in the first embodiment, congestion information of a road to bean LC scheduled zone is used in the determination of the level ofdifficulty of lane change control. When the road to be the LC scheduledzone is congested, the lane change control is likely to be difficult.Thus, the HCU 20 can accurately perform the level determination inadvance by using the congestion information as a travel environmentfactor. In addition, when the congestion information is presented to thedriver by the preliminary authority transfer, the driver can receive thecontrol from the automatic driving function after understanding thestate of the LC scheduled zone in detail.

Further, in the first embodiment, weather information in an LC scheduledzone is used in the determination of the level of difficulty of lanechange control. Also when the weather condition in the LC scheduled zoneis bad, the lane change control is likely to be difficult. Thus, the HCU20 can accurately perform the level determination in advance by usingthe weather information as a travel environment factor. In addition,when the weather information is presented to the driver by thepreliminary authority transfer, the driver can receive the control fromthe automatic driving function after understanding the state of the LCscheduled zone in detail.

Further, in the first embodiment, when a previously defined mergingpoint such as a merging point from an IC, a JCT, and a SA and a PA intoa main through lane is present on a route in a long and medium-termtravel plan, the zone estimator 31 estimates the occurrence of an LCscheduled zone. According to the estimation of the occurrence of the LCscheduled zone based on map information included in the map data asdescribed above, the HCU 20 can start a preliminary control transferwith sufficient time before a timing when a control transfer is started.

Further, in the first embodiment, when there is a temporary laneregulation on a route in a long and medium-term travel plan, the zoneestimator 31 estimates the occurrence of an LC scheduled zone. The HCU20 can more certainly estimate the occurrence of a situation in whichthe driver is forced to make a lane change without exception by usingtemporary traffic regulation information for the estimation of theoccurrence of the LC scheduled zone as described above.

In addition, in the preliminary authority transfer of the firstembodiment, the driver is notified of any of the travel environmentfactors including the structure information, the congestion information,and the weather information that raises the LC level as the reason of acontrol transfer. That is, the driver is notified of all travelenvironment factors that raise the LC level. Thus, the driver canreceive the control after understanding the state of the LC scheduledzone in more detail. In addition, as an estimated degree of difficultyof lane change control becomes higher, a message presented in thepreliminary authority transfer becomes longer. Thus, the driver cansensuously grasp the difficulty of lane change control in the LCscheduled zone which the driver is going to encounter and makepreparations for a driving change.

Further, in the first embodiment, as the level of difficulty of lanechange control becomes higher, the HCU 20 uses more alert devices 10 inthe preliminary authority transfer. Thus, when the possibility of adriving change is low, a preliminary authority transfer that is lesslikely to give the driver a troublesome feeling is performed. On theother hand, the driver is notified of information of a situation thathas a particularly high possibility of the occurrence of a drivingchange in the estimated LC scheduled zone without exception by aplurality of alert devices 10.

In the first embodiment, the HCU 20 corresponds to the “alert controlapparatus”, and the main processor 21 and the drawing processor 22correspond to the “processor”. Further, the zone estimator 31corresponds to the “estimator”, the determiner group 32 corresponds tothe “determiner”, and the preliminary notification device 52 correspondsto the “notification device”.

Second Embodiment

A second embodiment of the present disclosure illustrated in FIG. 5 is amodification of the first embodiment. An automatic driving ECU 260 ofthe second embodiment constructs a preliminary authority transferprocessor 30 and a main authority transfer processor 40 in addition tofunctional sections (61 to 64) which are substantially the same as thoseof the first embodiment by executing an automatic driving program by aprocessor 61 a (refer to FIG. 2). On the other hand, an HCU 220constructs an HMI controller 50 by executing an alert control program bya main processor 21 and a drawing processor 22 (refer to FIG. 2). Thatis, the preliminary authority transfer processor 30 and the mainauthority transfer processor 40 are not constructed in the HCU 220.

Also in the mode in which the preliminary authority transfer processor30 is constructed in the automatic driving ECU 260 as described above, apreliminary authority transfer based on estimation of the occurrence ofan LC scheduled zone can be performed. Thus, the second embodiment alsoachieves an effect similar to the effect of the first embodiment. Thedriver can initiatively receive control after previously understandingthe state of the LC scheduled zone and making advance preparations.Thus, the automatic driving ECU 260 and the HCU 220 can reduce atroublesome feeling of the driver such that the driver is forced tochange driving under the initiative of a system relating to theautomatic driving function. In the second embodiment, the automaticdriving ECU 260 and the HCU 220 correspond to the “alert controlapparatus”.

Third Embodiment

In a third embodiment of the present disclosure illustrated in FIG. 6 isanother modification of the first embodiment. An onboard network of thethird embodiment is provided with a transfer control ECU 330 which iselectrically connected to an automatic driving ECU 60 and an HCU 220.The transfer control ECU 330 is an electronic control unit mainlycomposed of a microcomputer which includes a processor, a RAM, a storagemedium, and an input/output interface. The transfer control ECU 330constructs a preliminary authority transfer processor 30 and a mainauthority transfer processor 40 which are substantially the same asthose of the first embodiment by executing a transfer control program bythe processor.

The third embodiment in which the preliminary authority transferprocessor 30 is constructed in the transfer control ECU 330 as describedabove also achieves an effect similar to the effect of the firstembodiment. The driver can initiatively receive control after previouslyunderstanding the state of the LC scheduled zone and making advancepreparations. Thus, the transfer control ECU 330 and the HCU 220 canreduce a troublesome feeling of the driver such that the driver isforced to change driving under the initiative of a system relating tothe automatic driving function. In the third embodiment, the transfercontrol ECU 330 and the HCU 220 correspond to the “alert controlapparatus”.

Other Embodiments

The plurality of embodiments have been described above. However, thepresent disclosure is not limited to the above embodiments and can beapplied to various embodiments and combinations within the range of thegist of the present disclosure.

The zone estimator in the above embodiments estimates the occurrence ofan LC scheduled zone on the basis of a merging point or a laneregulation. However, information used in the estimation of theoccurrence of an LC scheduled zone by the zone estimator is not limitedto the above information. The zone estimator can use various pieces ofinformation relating to a lane change in the estimation of theoccurrence of an LC scheduled zone.

Travel environment factors used in each of the determiners are notlimited to the structure information, the congestion information, andthe weather information as described in the above embodiments. Varioustravel environment factors relating to the difficulty of lane changecontrol can be used in the determination of the LC level by thedeterminers. Further, two travel environment factors or four or moretravel environment factors may be used in the determination of the LClevel in each of the determiners.

Further, each of the determiners of the above embodiments affirms ordenies the possibility of a driving change by comparing each previouslyset threshold with acquired information with regard to the gradient andthe distance of an acceleration section, a traveling speed of trafficflow, and the amount of rainfall and the amount of snowfall. However, adeterminer constructed by machine learning may determine the possibilityof a driving change.

A notification mode of the preliminary authority transfer may be changedaccording to not only travel environment factors, but also a state ofthe driver. For example, in a mode capable of acquiring a heart rate ora pulse rate of the driver as driver information, the HCU can detectimpatience of the driver. Thus, when the impatience of the driver hasbeen detected, the preliminary notification device can change thecontents of a message to contents that calm the driver down in thepreliminary authority transfer. Further, the preliminary notificationdevice can change a tone of a voice which performs the preliminaryauthority transfer to a tone having a calm atmosphere. Further, when areduction in the awaking level in the driver has been detected on thebasis of driver information detected by the detector, the preliminarynotification device 52 may perform adjustment for advancing a starttiming of the preliminary authority transfer.

The preliminary authority transfer of the above embodiments is startedat the timing when a grace period to start the authority transferbecomes a predetermined time. However, the preliminary notificationdevice may start the preliminary authority transfer on the basis of thedistance to the LC scheduled zone. Further, the preliminary notificationdevice may not notify the driver of all travel environment factors thatraise the LC level. For example, when the LC level is high, the drivermay be notified of only one of a plurality of travel environment factorsthat raise the LC level, the one travel environment factor making lanechange control most difficult.

The alert device used in the preliminary authority transfer can beappropriately changed. For example, an ultrasonic speaker may be used toreproduce a voice of the preliminary authority transfer so that only thedriver can hear the voice. Further, display of the preliminary authoritytransfer may be shown on a display surface of a display device thatdiffers from the HUD.

Each of the functions relating to the preliminary authority transfer maybe appropriately implemented by various electronic control units mountedon the vehicle as described in the above first to third embodiments.Further, various nontransitive and substantive storage media such as aflash memory and a hard disk can be employed as a configuration thatstores a program executed by each of the processors.

It is noted that a flowchart or the processing of the flowchart in thepresent application includes sections (also referred to as steps), eachof which is represented, for instance, as S101. Further, each sectioncan be divided into several sub-sections while several sections can becombined into a single section. Furthermore, each of thus configuredsections can be also referred to as a device, module, or means.

While the present disclosure has been described with reference toembodiments thereof, it is to be understood that the disclosure is notlimited to the embodiments and constructions. The present disclosure isintended to cover various modification and equivalent arrangements. Inaddition, while the various combinations and configurations, othercombinations and configurations, including more, less or only a singleelement, are also within the spirit and scope of the present disclosure.

1. An alert control apparatus that notifies a driver in advance of atransfer of control relating to a driving operation from an automaticdriving function to the driver by controlling at least one alert devicemounted on a vehicle, which is equipped with the automatic drivingfunction for performing the driving operation on behalf of the driver,the alert control apparatus comprising: a main authority transferprocessor that executes a main authority transfer process for notifyingthe driver of an execution of the transfer of the control when thecontrol is transferred from the automatic driving function to thedriver; an estimator that estimates an occurrence of a change executionsituation that requires a lane change under a condition in which thedriving operation of the vehicle is controlled by the automatic drivingfunction; a determiner that estimates a level of difficulty of lanechange control based on a plurality of travel environment factors in thechange execution situation estimated by the estimator, and determines apossibility of the transfer of the control from the automatic drivingfunction to the driver; and a notification device that starts apreliminary authority transfer notification before a grace period of astart of the transfer of the control executed by the main authoritytransfer processor, the preliminary authority transfer notificationnotifying the driver in advance of a possibility of the transfer of thecontrol together with a reason of the transfer of the control with anotification mode corresponding to the level determined by thedeterminer using the at least one alert device when the determinerdetermines the possibility of the transfer of the control.
 2. The alertcontrol apparatus according to claim 1, wherein: the determinerdetermines the level according to structure information of a road in thechange execution situation as one of the travel environment factors; andthe notification device provides a notification to the driver to includethe structure information as the reason of the transfer of the controlwhen the level is raised due to the structure information.
 3. The alertcontrol apparatus according to claim 1, wherein: the determinerdetermines the level according to congestion information of a road inthe change execution situation as one of the travel environment factors;and the notification device provides a notification to the driver toinclude the congestion information as the reason of the transfer of thecontrol when the level is raised due to the congestion information. 4.The alert control apparatus according to claim 1, wherein: thedeterminer determines the level according to weather information in thechange execution situation as one of the travel environment factors; andthe notification device provides a notification to the driver to includethe weather information as the reason of the transfer of the controlwhen the level is raised due to the weather information.
 5. The alertcontrol apparatus according to claim 1, wherein the estimator estimatesthe occurrence of the change execution situation when a previously setmerging point is disposed in a traveling direction of the vehicleaccording to map information in the traveling direction of the vehicle.6. The alert control apparatus according to claim 1, wherein theestimator estimates the occurrence of the change execution situationwhen a lane restriction is disposed in a traveling direction of thevehicle according to traffic restriction information acquired from anexternal device of the vehicle via communication.
 7. The alert controlapparatus according to claim 1, wherein the notification device notifiesthe driver of all the travel environment factors that raise the levelamong the travel environment factors used in determination of thedeterminer.
 8. The alert control apparatus according to claim 1,wherein: the at least one alert device includes a plurality of alertdevices; and the notification device increases a numerical number ofalert devices used in a notification of the transfer of the control asthe level becomes higher.
 9. An alert control method for notifying adriver in advance of a transfer of control relating to a drivingoperation from an automatic driving function to the driver bycontrolling at least one alert device mounted on a vehicle, which isequipped with the automatic driving function for performing the drivingoperation on behalf of the driver, the alert control method executed byat least one processor, comprising: estimating an occurrence of a changeexecution situation that requires a lane change under a condition inwhich the driving operation of the vehicle is controlled by theautomatic driving function; estimating a level of difficulty of lanechange control based on a plurality of travel environment factors in anestimated change execution situation, and determining a possibility ofthe transfer of the control from the automatic driving function to thedriver; starting a preliminary authority transfer notification before agrace period of a start of the transfer of the control executed inexecuting of a main authority transfer process, the preliminaryauthority transfer notification notifying the driver in advance of apossibility of the transfer of the control together with a reason of thetransfer of the control with a notification mode corresponding to adetermined level using the at least one alert device when determiningthe possibility of the transfer of the control; and executing the mainauthority transfer process for notifying the driver of an execution ofthe transfer of the control when the control is transferred from theautomatic driving function to the driver.